High-pressure single-crystal neutron diffraction
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Date
2016-11-29
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Publisher
Australian Institute of Nuclear Science and Engineering
Abstract
High-pressure neutron diffraction is always challenging, but it can offer several advantages over high-pressure X-ray diffraction to make meeting those challenges worthwhile. In addition to the usual higher sensitivity to low-X elements, notably hydrogen, and to magnetic moments, the low absorption by many pressure cell materials can yield greater reciprocal space coverage for single crystals. The low scattering power usually requires considerably larger sample volumes than with X-rays, but for the same reason the cell-wall materials can
be quite thick. Common cell designs include He-gas cells and simple clamp cells, opposed piston cells (e.g.
Bloch, McWhan), opposed-anvil cells (e.g. diamond anvil cell, Paris-Edinburgh cell), and multi-anvil cells, each adapted to sample volume, accessibility, pressure, and other external parameters, especially temperature, that suit the scientific question of interest. State-of-the art experiments using each cell type will be described.
A special challenge in high-pressure diffraction is to perform neutron and X-ray experiments on the same material under the same conditions. Previously, this meant using different cells and samples with achieving identical pressures a hit-or-miss affair. This has all changed with the recent demonstration on KOALA on the OPAL research reactor that modern neutron Laue diffraction can be performed on the same sample in the same diamond-anvil cell as used for laboratory X-ray experiments [1].
Description
Keywords
Neutron diffraction, X-ray diffraction, Pressure range mega pa 10-100, Magnetic moments, Hydrogen, Monocrystals, Laue method, OPAL Reactor
Citation
McIntyre, G. J., Binns, J., & Parsons, S. (2016). High-pressure single-crystal neutron diffraction. Paper presented at 13th AINSE-ANBUG Neutron Scattering Symposium, Sydney, NSW, Australia, 29-30 November 2016.